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Get A life

24 April 1999

By Dave Cliff

Virtual Organisms by Mark Ward, Macmillan, £12.99, ISBN 0333724828

MENTION “virtual organisms” and images of the Tamagotchi, Bandai’s electronic
pet, will spring into many people’s minds. If not provided with enough attention
from its owner, the pet gets bored; if not fed enough, it may die. The aim is to
hatch a pet and nurture it through to old age. The pet is lifelike in the
demands it makes of its owner, but without any of the real-life mess, smells or
inconvenience that flesh-and-blood pets impose.

But virtual organisms have a more serious side. Consider the plight of a
researcher studying the sudden, dramatically sharp increase in the number of
species in the fossil record around 570 million years ago. Was this phenomenon,
known as the Cambrian explosion, a one-off fluke, a flaw in the fossil record,
or an example of what we would expect to see in any evolving ecosystem?

In 1991, Thomas S. Ray, then professor of biology at the University of
Delaware, argued that, ideally, we would answer such questions by setting up
several solar systems, some identical and some differing by a few key
parameters. Then we would leave them alone for four or five billion years to see
what forms of life evolve.

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But we can’t. So instead Ray abstracted what he believed to be the key
aspects of evolutionary processes, and wrote a computer program that created a
virtual environment on his PC. There, virtual organisms could exist, interact
and evolve. Evolution in the computer simulation progressed at very high speeds,
allowing experiments to be completed in hours rather than years, and permitting
Ray to run multiple sequences of experiments and compare their results.

While the similarities between Ray’s results and the Cambrian Explosion data
are still the subject of debate, there is a philosophical issue at stake as
well. Ray has argued forcefully that while such software systems could be
interpreted as models or simulations of life on Earth, they could also be viewed
as independent instances of life. That is, the virtual organisms in Ray’s
computer may actually be considered to be alive, if one accepts that “life” may
be a property of how matter is organised, rather than of specific types of
matter—such as the carbon-chain molecules studied in organic
chemistry.

Like the Tamagotchi, Ray’s virtual organisms save on food and cleaning
bills—quite considerably, given the inconvenient billion-year running-time
of the real thing. Toys and science have more recently come together in several
ways, from the TechnoSphere project, a 3D model world inhabited by artificial
life forms created by Web users, to Mindscape’s Creaturesgame, where
players create their own evolution. Mark Ward, however, makes no mention of such
frivolities. In Virtual Organisms he deals only with advances in a
scientific field at the intersection of biology and computer science: a
field known as artificial life, or more commonly as A-Life.

Computer simulations offer biologists the opportunity to study phenomena that
would be impossible to study in real systems. The inspiration works in reverse,
too: a number of computer scientists, disappointed by the results of artificial
intelligence research, have turned to biology.

IBM’s Deep Blue chess computer may have beaten Gary Kasparov, but it tells us
little or nothing about what processes go on in a chess player’s head. It tells
us nothing about any other aspect of human intelligence, such as how we
recognise a Cézanne or generate an English sentence. Moreover, many
problems which are very simple to define—such as designing a
telecommunications network using the absolute minimum of cable —cannot be
solved exactly in reasonable time.

A notable example of biology inspiring the science behind computer software
is the genetic algorithm, which uses Darwin’s principles of random variation and
directed selection to search a range of possible solutions to a problem, often
with great success. In hardware, autonomous multilegged insect-like robots can
scramble over uneven terrain without requiring remote control from a human.
Genetic algorithms have been used to design hardware such as electronic circuits
for robots.

Ward covers all this in his book. It might serve as a useful introduction for
readers to whom all of this is new. But how much does it add? A-Life research
achieved a high media profile fairly rapidly following the first international
workshop in September 1987. This was helped by the publication of several
excellent popular science books, the most notable of which were W. Mitchell
Waldrop’s Complexity (1992), Steven Levy’s Artificial Life
(1993), and Peter Coveney and Roger Highfield’s Frontiers of Complexity
(1995). All three are highly readable, with content that remains very
relevant.

Ward’s book suffers in comparison with these older texts, for three reasons.
The first is that, while his text is very good in places, other parts seem to
have been written in a hurry, and editorial standards are generally lower than
for the earlier books. I doubt whether anyone who reads this book without prior
knowledge will form an accurate idea of what a genetic algorithm is, or what
entropy measures, or how a neural network operates.

The final chapter contains fairly wild speculations, which I assume are
Ward’s because they are not attributed to anyone else, but he then dismisses
them in the last paragraph.

The third problem is that there is little here about A-Life that is not
covered in the earlier texts. It is hard to avoid the conclusion that the early
breakthroughs have yet to be consolidated by significant results. Two
exceptions, which Ward discusses in some depth, are the application of A-Life
techniques in telecommunications routing software and the use of genetic
algorithms to evolve hardware circuits.

That Ward’s prose lacks the clarity of previous books on the subject should
be of no concern to A-Life researchers. That it also lacks the immediacy and
sense of anticipation that the earlier authors managed to convey is perhaps more
worrying. While some A-Life practitioners might attribute this to a failing in
Ward’s style, it is tempting to wonder whether this is actually an accurate
reflection of a research field that once showed early promise but in which
progress is now slowing.